Zoom documentation for keyboard shortcuts:
https://support.zoom.us/hc/en-us/articles/205683899-Hot-keys-and-keyboard-shortcuts

Commonly used keyboards shortcuts:
Video start/stopAlt+V
Audio Mute/unmuteAlt+A

We have had some issues with specific browsers working with Zoom. Our recommendation is to download and install the Zoom software prior to the meeting.
Here is a link to the Zoom App download page: https://zoom.us/download. Both Windows and MacOS versions of the app are available to download.

The Zoom app software to install are also available here:
MacOS: https://zoom.us/download
Windows: https://zoom.us/download

For witness testimony:
The Colorado General Assembly uses Zoom Events (not Webex Meetings) for remote participation in committee hearings. When a witness joins Zoom events, they join as an attendee. An attendee can only listen unless un-muted to speak by the Zoom host. Attendees do not have the ability to show video, un-mute, or screen share. That is, until the Zoom host promotes the attendee to a panelist once it is their time to talk. When the committee chairperson calls the witness to speak, the Zoom host will promote the witness to be a panelist. Once you become a panelist, the Zoom controls for video, and un-mute audio will then be available and function as intended.